summary of nutrient companies products and their benefits

I'm not there yet, but I will be soon enough. You have a strong recomendation for the Liquid Karma. However, I was wondering about a recomendation for Bud Boosters:

"Advanced Nutrients Big Bud - is Big Bud's plant specific ratios of Phosphorous, Potassium, Magnesium and Amino Acids. Big Bud will dramatically increase bud growth, width, weight and resin production like no other bloom enhancing product can."

Few questions.

1) does this work in conjunction with my normal feeding schedule. I am currently useing GH 3-part Grow, Micro and Bloom. Does this replace the Bloom or added to it?

2) Also, I am using Liquid Karma, Hygrozyme and Cal-Mg. Can I still add the Big Bud with these other suppliments?

3) When is Big bud or other bud enhansers added? It says 3-4 weeks. Is that 3-4weeks prior to harvest? Or only use for 3-4 weeks as soon as I set my lights to 12/12?

Sorry if these seem like stupid questions. I'm a bit new to additions to normal feeding. I just stared using Liquid Karma and Hygrozyme based on this post. So I thank you for the quality of the info you are providing. It is helping a lot.